Force input operation device, movable body, carrying vehicle, and auxiliary vehicle for walking

ABSTRACT

A manipulator for a mobile object which allows operating the mobile object with a natural feeling without difficulty irrespective of the physical condition of the user, and a push cart and a walker including such a manipulator are to be provided. The straight travel reference vector Fs, direction change reference vector Fc and rotating reference vector Fr are developed in advance based on the applied manipulating force of the user. An angle defined by the vector of the manipulating force applied by the user (applied manipulating force vector Fi) and the straight travel reference vector Fs is denoted as α, an angle defined by the applied manipulating force vector Fi and the direction change reference vector Fc as β, and an angle defined by the applied manipulating force vector Fi and the rotating reference vector Fr as γ. Herein the angles are illustrated as α&lt;β&lt;γ, and the moving mode (straight travel mode in this example) is selected in relation with the reference manipulating force vector (the straight travel reference vector Fs in this example) that makes the smallest angle (α).

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/JP2004/1657 which has an Internationalfiling date of Feb. 16, 2004 and designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to a force input manipulator that selectsfor example an operation mode out of a plurality of operation modes of amobile object, according to a manipulating force applied to amanipulating unit such as a handle, and thereby outputs a signal thatcontrols a motion of the mobile object, as well as to a mobile objectoperated by such a force input manipulator, and a push cart and a walkerin which the force input manipulator is incorporated.

BACKGROUND ART

A conventional mobile object such as a push cart or a walker is designedto detect a manipulating force of a user applied to a manipulating unit,and to select an operation mode such as moving straight, changing adirection or rotating, according to the manipulating force. In such aconventional mobile object, the manipulating force is predetermined at afixed level for each mechanism, and hence the user has to apply a forcegreater than a certain level in order to operate the mobile object,otherwise the mobile object cannot be operated, and in particular, theoperation mode cannot be selected. For example, although a physicallychallenged person with limited power tries to manipulate themanipulating unit to switch the operating mode, the person is oftenunable to apply the manipulating force that satisfies the levelpredetermined for detecting the manipulating force, and thus inhibitedfrom operating the mobile object as desired. Also, when the directionthat the user can apply a force is biased, the mobile object may move ina direction different from the intention of the user. (Refer to JapanesePatent Application Laid-Open No.2002-2490, pamphlet under InternationalPublication No. WO98/41182)

As stated above, a conventional mobile object has a drawback that thedetection level of the applied manipulating force is fixed, and thattherefore it is impossible or difficult to operate the mobile objectwhen the detection level of the mobile object with respect to theapplied manipulating force is different from the level of themanipulating force that the user can apply. In addition, when thedirection that the user can apply a force is biased, the mobile objectmay move in a direction different from the intention of the user.

DISCLOSURE OF THE INVENTION

The present invention has been conceived in view of the foregoingproblems, and proposes to determine a detection level with respect to amanipulating force applied, based on a manipulating force that a usercan usually apply. In other words, it is an object of the presentinvention to provide a force input manipulator that determines andstores a reference manipulating force according to a manipulating forcethat a user can apply with respect to each operation mode, to therebyallow the user, despite being able to only apply a manipulating force ofa low (weak) level, to manipulate as desired through a natural feelingwithout finding difficulty in manipulating, as well as a mobile objectprovided with such force input manipulator.

The foregoing object includes providing a force input manipulator thatoffers easy and natural manipulating feeling to all types of usersincluding ordinary users, physically weak users, and users who can onlyapply a force in a limited direction, based on the function of setting areference manipulating force according to a manipulating force appliedto the manipulating unit, as well as a mobile object provided with suchforce input manipulator.

It is another object of the present invention to provide a push cart ora walker, by constituting the mobile object as a push cart or a walker,which offers easy and natural manipulating feeling to all types of usersincluding a user who utilizes the mobile object as a push cart, and auser who utilizes the mobile object as a walker.

A first aspect of the present invention provides a force inputmanipulator that operates an object according to a manipulating forceapplied to a manipulating unit, comprising an applied force detectorwhich detects the manipulating force applied to the manipulating unit;an operation mode selector which decides a reference manipulating forceclosest to the detected manipulating force applied out of a plurality ofreference manipulating forces stored in advance in correlation with aplurality of operation modes, and selects the operation modecorresponding to the decided reference manipulating force; and a motioncontrol signal generator which outputs a motion control signal forcontrolling the motion of the object according to the selected operationmode.

Since the force input manipulator according to the first aspect decidesthe closest reference manipulating force upon comparison with theplurality of reference manipulating forces stored in advance incorrelation with the operation modes, and selects the operation modecorresponding to the decided reference manipulating force is selected, auser-friendly force input manipulator can be achieved which allows theuser to select the operation mode as desired even when the user can onlyapply a limited manipulating force to the manipulating unit. Such forceinput manipulator offers a natural manipulating feeling also to anordinary user. In addition, the force input manipulator allows a user,who can only apply a force in a limited direction, to correctly selectthe desired operation mode, thereby equally providing its advantage ofuser-friendliness.

A second aspect of the present invention provides the force inputmanipulator according to the first aspect, further comprising means fordeveloping and storing the reference manipulating force based on theapplied manipulating force.

The force input manipulator according to the second aspect is capable ofdeveloping the reference manipulating force based on the manipulatingforce actually applied to the manipulating unit, and hence establishingan appropriate reference manipulating force in advance according to asmall manipulating force applied by a physically weak user, therebyachieving a user-friendly force input manipulator which can decide areference manipulating force according to the intention of the user, andallow the user to smoothly select the operation mode.

A third aspect of the present invention provides the force inputmanipulator according to the first or the second aspect, wherein theapplied force detector is a biaxial force sensor that detects a forceacting in a direction with respect to the object and in anotherdirection intersecting the first mentioned direction.

According to the third aspect, since a biaxial force sensor is employedas the applied force detector, the manipulating force can be detected bya relatively simple device, and therefore the operation mode can beeasily and accurately selected according to the intention of the user.

A fourth aspect of the present invention provides a force inputmanipulator according to the first or the second aspect, wherein theapplied force detector includes a plurality of force sensors, out ofwhich at least two sensors are employed for one direction.

According to the fourth aspect, since the applied force detectorincludes a plurality of force sensors, out of which at least two sensorsare employed for each direction, a rotating manipulating force, in adirection of an axis orthogonal to an axis for which two sensors areprovided, can be relatively easily but accurately detected, andtherefore the operation mode can be easily and accurately selectedaccording to the intention of the user.

A fifth aspect of the present invention provides a force inputmanipulator according to the first to the fourth aspects, wherein theoperation mode is one of moving straight, changing a direction androtating.

According to the fifth aspect, the intention of the user can be easilyrecognized among moving straight, changing a direction and rotating(rotation on the spot), according to the applied manipulating force, andtherefore the operation mode can be easily and accurately decided andselected according to the intention of the user.

A sixth aspect of the present invention provides a force inputmanipulator according to the first to the fifth aspects, wherein theoperation mode selector stores a decision region defined by a magnitudeand acting direction of the force with respect to each referencemanipulating force, so as to specify the decision region to which theapplied manipulating force belongs, based on the magnitude and actingdirection thereof, and thus to decide the reference manipulating forceclosest to the applied manipulating force.

According to the sixth aspect, the intention of the user represented bythe applied manipulating force can be easily recognized among movingstraight, changing a direction and rotating, according to the definitionof the decision region, and therefore the operation mode can be easilyand accurately decided and selected according to the intention of theuser.

A seventh aspect of the present invention provides a force inputmanipulator according to the first to the fifth aspects, wherein theoperation mode selector has a function of deciding the referencemanipulating force closest to the applied manipulating force, based on adifference in direction between the acting direction of the appliedmanipulating force and that of the reference manipulating force.

According to the seventh aspect, the intention of the user can be easilyrecognized among moving straight, changing a direction and rotating,according to the difference in direction between the acting direction ofthe applied manipulating force and that of the reference manipulatingforce, and therefore the operation mode can be easily and accuratelydecided and selected according to the intention of the user.

An eighth aspect of the present invention provides a force inputmanipulator according to the first to the fifth aspects, wherein theoperation mode selector has a function of utilizing the magnitude andacting direction of the applied manipulating force and those of thereference manipulating force to calculate a distance in atwo-dimensional space defined by the magnitude and the direction, anddeciding the reference manipulating force closest to the appliedmanipulating force based on the length of the calculated distance.

According to the eighth aspect, the magnitude and acting direction ofthe applied manipulating force and those of the reference manipulatingforce are utilized to calculate a distance in a two-dimensional spacedefined by the magnitude and the direction, and the intention of theuser can be easily recognized among moving straight, changing adirection and rotating based on the length of the calculated distance,and therefore the operation mode can be easily and accurately decidedand selected according to the intention of the user, even when theapplied manipulating force is small.

A ninth aspect of the present invention provides a mobile objectcomprising the force input manipulator according to any of the first tothe eighth aspect, so as to move according to the motion control signaloutput by the motion control signal generator.

A tenth aspect of the present invention provides a push cart comprisingthe mobile object according to the ninth aspect.

An eleventh aspect of the present invention provides a walker comprisingthe mobile object according to the ninth aspect.

According to the ninth to the eleventh aspects, a user-friendly mobileobject, a push cart and a walker can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1C are plan views showing operation modes of a mobile objectprovided with a force input manipulator according to a first embodimentof the present invention;

FIG. 2 is a perspective view showing an outline of the force inputmanipulator according to the first embodiment, incorporated in themobile object for selecting an operation mode;

FIG. 3 is a vector diagram showing examples of reference manipulatingforces according to the present invention;

FIG. 4 is a vector diagram for explaining a process to select theoperation mode by comparison of an applied manipulating force and thereference manipulating force, in the force input manipulator accordingto the first embodiment;

FIG. 5 is a vector diagram for explaining another process to select theoperation mode by comparison of an applied manipulating force and thereference manipulating force, in the force input manipulator accordingto the first embodiment;

FIG. 6 is a block diagram showing an outline of a control blockaccording to the present invention;

FIG. 7 is a flowchart showing a process of operation mode selection andoperating speed calculation, in the force input manipulator according tothe first embodiment;

FIG. 8A is a perspective view and FIG. 8B is a plan view, respectivelyshowing a mobile object provided with a force input manipulatoraccording to a second embodiment of the present invention;

FIG. 9 is a plan view showing an outline of the force input manipulatoraccording to the first embodiment, incorporated in the mobile object forselecting the operation mode;

FIG. 10 is a block diagram showing an outline of another control blockaccording to the present invention; and

FIG. 11 is a flowchart showing a process of operation mode selection andoperating speed calculation, in the force input manipulator according tothe second embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereunder, the present invention will be described based on theaccompanying drawings illustrating the embodiments thereof.

First Embodiment

FIGS. 1A to 1C are plan views showing operation modes of a mobile objectprovided with a force input manipulator according to the firstembodiment of the present invention. In these drawings, numeral 1designates the mobile object, for example a push cart (electric cart)and a walker (electric walker), utilized for assisting a person havingdifficulty in walking. The mobile object 1 is provided with for examplefour sets of wheels. FIGS. 1A to 1C depict the status of each wheel ofthe mobile object 1, seen through from above. The four sets of wheelsare respectively denoted as a right front wheel 1 a, right rear wheel 1b, left front wheel 1 c and left rear wheel 1 d. On the mobile object 1,a force input manipulator 2 is mounted. A user applies a manipulatingforce to the force input manipulator 2 when necessary, so as to selectan operation mode of the mobile object 1. In the first embodiment, theoperation modes include a straight travel mode (a), direction changemode (b) and rotation mode (c). These three basic operation modes enableall types of movements. The operation modes may be classified in furtherdetails.

In FIG. 1A, all of the right front wheel 1 a, right rear wheel 1 b, leftfront wheel 1 c and left rear wheel 1 d are oriented in a straight line,so as to move straight in a direction indicated by the arrow A. In FIG.1B, the right front wheel 1 a and left front wheel 1 c are oriented tothe right, to which the moving direction is being changed as indicatedby the arrow B, while the right rear wheel 1 b and left rear wheel 1 dare oriented to the left, thus to facilitate the direction change to theright. In FIG. 1C, the right front wheel 1 a and left front wheel 1 care oriented to an inner forward direction of the mobile object 1, whilethe right rear wheel 1 b and left rear wheel 1 d are oriented to anouter forward direction, so that the mobile object turns around to theright, as indicated by the arrow C. Each of these operation modes can beselected according to a manipulating force applied to the force inputmanipulator 2. Also, the orientation control (steering control) anddrive control of the wheels are performed by a steering unit (not shown)with a known technique, for steering and driving the wheels.

FIG. 2 is a perspective view showing an outline of the force inputmanipulator 2 according to the first embodiment, incorporated in themobile object for selecting the operation mode. The force inputmanipulator 2 includes a manipulating handle 2 a which corresponds tothe manipulating unit, a handle clamp 2 b which fastens the manipulatinghandle 2 a, a biaxial force sensor 2 c connected to the handle clamp 2 bfor detecting a manipulating force applied to the manipulating handle 2a, and a joint portion 2 d for attaching the force input manipulator 2to the main body (not shown) of the mobile object 1. The arrow Aindicates for example a moving direction (Y-axis), and the arrow Bindicates for example a left and right direction (X-axis). The biaxialforce sensor 2 c serves as the applied manipulating force detector (Ref.applied manipulating force detector 3 in FIG. 6), which detects a forceacting in the moving direction and in left and right direction, andtransmits the detected result to the operation mode selector (Refoperation mode selector 4 in FIG. 6). The operation mode selectorselects a required operation mode based on the detected result, so thatthe mobile object 1 is driven in the desired operation mode.

FIG. 3 is a vector diagram showing examples of reference manipulatingforces according to the present invention. As an example, the Y-axiscorresponds to the moving direction (back and forth direction), and theX-axis corresponds to left and right direction with respect to themoving direction. The first quadrant is divided into three regions to beallocated to the operation mode. For example, a partition line L1delimits a region A1 and a region A2, and a partition line L2 delimitsthe region A2 and a region A3. The region A1 corresponds to the straighttravel mode; the region A2 corresponds to the direction change mode (inthe case a left turn); and the region A3 corresponds to the rotationmode (in this case rotation to the left). The method of dividing theregions for deciding the operation mode is not limited to this example,but the regions may be divided as desired according to a position of theendpoint of the vector of the applied manipulating force. Sucharrangement allows properly dividing the regions for deciding theoperation mode, elaborately incorporating peculiar manipulatingtendencies that are different among individual users.

In each region, a reference manipulating force (reference manipulatingforce vector) is developed for each operation mode in relation with arepresentative applied manipulating force, namely a straight travelreference vector Fs, direction change reference vector Fc, and rotatingreference vector Fr. These reference manipulating force vectors areappropriately developed in advance according to the magnitude of thereference manipulating force, and stored as a memory. Here, thereference manipulating force may be appropriately determined based on arepresentative output value of the biaxial force sensor, to be outputaccording to the manipulating force (applied manipulating force, appliedmanipulating force vector) actually applied by the user. The straighttravel reference vector Fs represents the reference manipulating forcein the straight travel mode; the direction change reference vector Fcrepresents the reference manipulating force in the direction changemode; and the rotating reference vector Fr represents the referencemanipulating force in the rotation mode.

For developing the reference manipulating force, the force inputmanipulator may be set in the reference manipulating force developingmode by the reference manipulating force developing means (not shown),and the reference manipulating force is determined for each user andeach operation mode, and stored as a memory. To be more detailed, theuser actually applies a manipulating force to the force inputmanipulator in each operation mode, and such manipulating force detectedby the applied manipulating force detector 3 is stored as a referencevalue in the reference manipulating force storage unit (Ref referencemanipulating force storage unit 5 in FIG. 6). For example in thestraight travel mode, the user applies a force that is comfortable tohim/her to the manipulating handle 2 a to a forward direction, and theforce detected at that moment is stored as a “straight travel modereference manipulating force” (straight travel reference vector Fs),upon pressing a straight travel mode setting button provided in thereference manipulating force developing means. In the case of therotation mode, the user applies a force that is comfortable to him/herto the manipulating handle 2 a from the left toward the right (in a plusdirection along the X-axis), and the force detected at that moment isstored as a “(left) rotation mode reference manipulating force”(rotating reference vector Fr), upon pressing a (left) rotation modesetting button provided in the reference manipulating force developingmeans. In the case of the direction change mode, the user applies aforce that is comfortable to him/her to the manipulating handle 2 a from45 degrees backward to the left to 45 degrees forward to the right, andthe force detected at that moment is stored as a “left turn modereference manipulating force” (direction change reference vector Fc),upon pressing a left turn mode setting button provided in the referencemanipulating force developing means.

The reference manipulating force may be individually developed fordifferent users. Developing the individual reference manipulating forcefor each user through the reference manipulating force developing meansallows reflecting a peculiar tendency or unique character of the user tothe reference manipulating force, and thus setting an appropriatereference manipulating force for each operation mode based on amanipulating force that is convenient (comfortable) to the user, evenwhen the user is physically challenged. It is also possible to let eachuser repeatedly apply a manipulating force in each operation mode in thereference manipulating force developing mode, so as to utilize anaverage manipulating force as the reference manipulating force in eachoperation mode.

FIG. 4 is a vector diagram for explaining a process to select theoperation mode by comparison of an applied manipulating force and thereference manipulating force, in the force input manipulator 2 accordingto the first embodiment. The following description is made on theassumption that the straight travel reference vector Fs, directionchange reference vector Fc and rotating reference vector Fr have beendeveloped in advance based on the applied manipulating force of theuser. For example, a vector of a manipulating force actually applied bythe user with an intention to select the operation mode is denoted as anapplied manipulating force vector Fi. An angle defined by the appliedmanipulating force vector Fi and the straight travel reference vector Fsis denoted as α, an angle defined by the applied manipulating forcevector Fi and the direction change reference vector Fc as β, and anangle defined by the applied manipulating force vector Fi and therotating reference vector Fr as γ, and the reference manipulating forceclosest to the manipulating force applied by the user with the intentionof selecting the operation mode is decided, based on a correlation(relation in magnitude) among the angles α, β and γ. In FIG. 4, theangles are illustrated as α<β<γ, and therefore the referencemanipulating force (reference manipulating force vector) that makes thesmallest angle (the angle α in this example), i.e. the straight travelreference vector Fs is selected, and hence the operation modecorresponding to the straight travel reference vector Fs, i.e. thestraight travel mode is selected.

The method of selecting the operation mode is not limited to theforegoing method of deciding the reference manipulating force closest tothe applied manipulating force directly from the angles, and thusselecting the operation mode.

For example, FIG. 5 is a vector diagram for explaining another processto select the operation mode by comparison of an applied manipulatingforce and the reference manipulating force, in the force inputmanipulator 2 according to the first embodiment. A vector of amanipulating force actually applied by the user with an intention toselect an operation mode is denoted as an applied manipulating forcevector Fi. A distance between the endpoint of the applied manipulatingforce vector Fi and the endpoint of the straight travel reference vectorFs is denoted as D1; a distance between the endpoint of the appliedmanipulating force vector Fi and the endpoint of the direction changereference vector Fc as D2; and a distance between the endpoint of theapplied manipulating force vector Fi and the endpoint of the rotatingreference vector Fr as D3; and the reference manipulating force closestto the manipulating force applied by the user with the intention ofselecting an operation mode is decided, based on a correlation (relationin length) among the distances D1, D2 and D3. In FIG. 5, the distancesare illustrated as D2<D1<D3, and therefore the reference manipulatingforce (reference manipulating force vector) corresponding to theshortest distance (the distance D2 in this example), i.e. the directionchange reference vector Fc is selected, and hence the operation modecorresponding to the direction change reference vector Fc, i.e. thedirection change mode is selected.

Alternatively, a projection of the applied manipulating force vector(projected vector) with respect to each reference manipulating forcevector may be developed so as to decide the reference manipulating force(reference manipulating force vector) closest to the appliedmanipulating force (applied manipulating force vector), and to therebyselect the operation mode. For example, when the magnitude (length)|Fis| of a projected straight travel vector Fis, which is the projectedvector of the applied manipulating force vector Fi with respect to thestraight travel reference vector Fs, is denoted as Ficosα; the magnitude(length) |Fic| of a projected direction change vector Fic, which is theprojected vector of the applied manipulating force vector Fi withrespect to the direction change reference vector Fc, is denoted asFicosβ; and the magnitude (length) |Fir| of a projected rotating vectorFir, which is the projected vector of the applied manipulating forcevector Fi with respect to the rotating reference vector Fr, is denotedas Ficosγ, since the vector magnitudes can be described asFicosα>Ficosβ>Ficosγ in this example, the straight travel referencevector Fs, which corresponds to the projected straight travel vector Fishaving the closest magnitude to the magnitude (length) |Fi| of theapplied manipulating force vector Fi, is decided as the referencemanipulating force (reference manipulating force vector), and hence theoperation mode corresponding to the straight travel reference vector Fs,i.e. the straight travel mode is selected.

The projection of the applied manipulating force vector (projectedvector) with respect to each reference manipulating force vector is alsoutilized in calculating a motion speed in each operation mode, as willbe subsequently described. For example, a moving speed (running speed)in the straight travel mode can be determined based on the magnitudeFicosα of the projected straight travel vector Fis.

In addition, a multi-parameter evaluation function may be generated bycombination of the foregoing methods, for selecting the operation mode.Such arrangement allows executing more realistic selection of theoperation mode.

FIG. 6 is a block diagram showing an outline of a control blockaccording to the present invention. A manipulating force applied to themanipulating handle 2 a, which is the manipulating unit, is detected bythe applied manipulating force detector 3. The applied manipulatingforce detector 3 is specifically a biaxial force sensor, as alreadystated. Naturally, employing a sensor having increased detecting axes(such as a hexaxial sensor) allows performing more precise (moremultidimensional) detection. At the operation mode selector 4, theapplied manipulating force (applied manipulating force vector Fi)detected by the applied manipulating force detector 3 is compared withthe reference manipulating force (reference manipulating force vector,such as the straight travel reference vector Fs, direction changereference vector Fc and rotating reference vector Fr) determined inadvance and stored in the reference manipulating force storage unit 5,so as to decide the reference manipulating force closest to the appliedmanipulating force, and to thereby select the operation modecorresponding to the reference manipulating force. In other words, theoperation mode selector 4 decides the reference manipulating forceclosest to the applied manipulating force out of a plurality ofreference manipulating forces developed and stored in advance withrespect to a plurality of operation modes (for example, one out of thestraight travel reference vector Fs, direction change reference vectorFc and rotating reference vector Fr), and then selects the operationmode corresponding to the reference manipulating force. The referencemanipulating force storage unit 5 may be a built-in memory or a portableauxiliary storage device such as a memory card containing the data ofeach individual user.

The motion control signal generator 6 calculates the motion speedrequired by motors 8 a to 8 d installed on the mobile object 1 fordriving the wheels, according to the selected operation mode, andoutputs a control signal corresponding to the motion speed to motorcontrollers 7 a to 7 d. The motor controllers 7 a to 7 d supply apredetermined driving current to the motors 8 a to 8 d respectively,according to the control signal from the motion control signal generator6. In FIG. 6, the motors are shown as the left driving motor 8 a, rightdriving motor 8 b, left steering motor 8 c and right steering motor 8 d,as an example. Here, the motion speed can also be calculated based onthe magnitude of the projection of the applied manipulating force(applied manipulating force vector), i.e. the projected vector, withrespect to each reference manipulating force vector, as describedreferring to FIG. 4. In addition, it is appropriate to develop controlparameters for the motion speed according to the operation mode, and amethod of developing the control parameters such as a straight motionspeed and rotational angular speed will be described hereunder indetails referring to FIG. 7.

FIG. 7 is a flowchart showing a process of operation mode selection andoperating speed calculation, in the force input manipulator 2 accordingto the first embodiment. The following description is based on theassumption that the operation modes include three modes, namely thestraight travel mode, direction change mode (left turn or right turnmode) and rotation mode.

Firstly, the applied manipulating force detector 3 detects the appliedmanipulating force (applied manipulating force vector) Fi (step S1). Inother words, the biaxial force sensor detects the force in bothdirections along the X-axis and Y-axis. Here, the X component of theapplied manipulating force Fi may be denoted as Fix, and Y component ofthe same as Fiy. Then it is decided whether the magnitude of the appliedmanipulating force Fi (length of the vector |Fi|=√(square of Fix+squareof Fiy)) is below a predetermined value (a threshold value k) (step S2).If the magnitude of the applied manipulating force Fi is decided to beless than the threshold value k (YES at S2), it is decided that theoperation mode intended by the user is the straight travel mode, and thespeed is zero (i.e. in a stop mode) (step S3). If the magnitude of theapplied manipulating force Fi is decided to be equal to or greater thanthe threshold value k (NO at S2), it is decided that the user intendsanother mode than the stop mode.

Then the operation mode selector 4 calculates the similarity (proximity)to the reference manipulating force developed according to the appliedmanipulating force Fi and the operation mode and stored in the referencemanipulating force storage unit 5 (step S4). In other words, theoperation mode selector 4 calculates the magnitude of the projection(projected vector) of the applied manipulating force (i.e. the magnitude|Fis| of the projected straight travel vector Fis, the magnitude |Fic|of the projected direction change vector Fic, and the magnitude |Fir| ofthe projected rotating vector Fir), with respect to the referencemanipulating force corresponding to the operation mode (such as thestraight travel reference vector Fs, direction change reference vectorFc and rotating reference vector Fr).

The reference manipulating force corresponding to the largest (closest)projected vector out of the calculated projection magnitudes of theapplied manipulating force is decided and retrieved, and the operationmode corresponding to the decided and retrieved reference manipulatingforce is selected. For example, firstly it is decided whether theapplied manipulating force corresponds to the straight travel mode,depending on whether the magnitude |Fis| of the projected straighttravel vector Fis is the greatest (step S5). If the magnitude of theprojected straight travel vector Fis is the greatest (YES at S5), theoperation mode selector 4 selects the straight travel mode (step S6).When the straight travel mode is selected, the motion control signalgenerator 6 calculates the straight moving speed to execute the straighttravel mode (step S7). Calculating the straight moving speed (movingspeed in the straight travel mode) in proportion to the magnitude |Fis|of the projected straight travel vector Fis provides highercontrollability in operating the mobile object 1.

If the magnitude of the projected straight travel vector Fis is not thegreatest (NO at S5), it is decided whether the applied manipulatingforce corresponds to the rotation mode, depending on whether themagnitude of the projected rotating vector Fir is the greatest (stepS8). If the magnitude of the projected rotating vector Fir is decided tobe the greatest (YES at S8), the operation mode selector 4 selects therotation mode (step S9). When the rotation mode is selected, the motioncontrol signal generator 6 calculates the rotational angular speed toexecute the rotation mode (step S10). Calculating the rotational angularspeed for the rotating motion in proportion to the magnitude |Fir| ofthe projected rotating vector Fir provides higher controllability inoperating the mobile object 1.

If the magnitude of the projected rotating vector Fir is not thegreatest (NO at S8), the operation mode selector 4 selects the directionchange mode (step S11). When the direction change mode is selected, themotion control signal generator 6 calculates the moving speed in acircumferential direction (circumferential speed) in the turning motionand the rotational angular speed with respect to the center of rotation,so as to execute the direction change mode (step S12). Calculating thecircumferential speed in proportion to the Y component Fiy of theapplied manipulating force Fi, and the rotational angular speed inproportion to the X component Fix of the applied manipulating force Fiprovides higher controllability in operating the mobile object 1.

Based on the setting and calculating results of the steps S3, S7, S10and S12, the motor controllers 7 a to 7 d accordingly determines aninstruction value for the motors, and outputs the value as a motorinstruction value (step S13). Repeating the foregoing steps according tothe cases leads to achieving the force input manipulator that cansmoothly operate the mobile object 1 based on the intention of the user.Also, incorporating a mobile object provided with such a force inputmanipulator in a push cart or a walker so as to operate the push cart orwalker can accomplish a user-friendly push cart or walker.

Second Embodiment

FIG. 8A is a perspective view and FIG. 8B is a plan view, respectivelyshowing a mobile object provided with a force input manipulatoraccording to a second embodiment of the present invention. In FIG. 8A,the numeral 1 designates a mobile object such as an electric cart, usedfor facilitating transportation of an object that is difficult to carry.The mobile object 1 is provided with, for example, four sets of wheels.FIG. 8B depicts the status of each wheel of the mobile object 1, seenthrough from above. The four sets of wheels are respectively denoted asa right front wheel 1 g, right rear wheel 1 e, left front wheel 1 h andleft rear wheel 1 f In the first embodiment, only the right rear wheel 1e and the left rear wheel 1 f are driven wheels, which are fixed to acasing of the mobile object 1. the right front wheel 1 g and left frontwheel 1 h are pivotally attached to the casing of the mobile object 1,so as to rotate according to a moving direction thereof. On the mobileobject 1, a force input manipulator 2 is mounted. A user applies amanipulating force to the force input manipulator 2 when necessary, soas to select an operation mode of the mobile object 1. In the secondembodiment, the operation modes include a straight travel mode,direction change mode and rotation mode, as in the first embodiment.These three basic operation modes enable all types of movements. Theoperation modes may be classified in further details.

In the straight travel mode indicated by the arrow A in FIG. 8B, boththe right rear wheel 1 e and left rear wheel 1 f rotate in a directionof straight forward movement at a same rotation speed. In the mode ofturning to the right as indicated by the arrow B, the right rear wheel 1e and left rear wheel 1 f are caused to rotate in different rotationspeed and directions, according to the turning radius. In the mode ofrotating to the right as indicated by the arrow C, the right rear wheel1 e and left rear wheel 1 f are caused to rotate in a same speed, but inthe opposite direction. In this way, controlling the rotation of onlythe left and right rear wheels allows changing the operation mode of themobile object 1, and the operation modes can be selected according to amanipulating force applied to the force input manipulator 2.

FIG. 9 is a plan view showing an outline of the force input manipulator2 according to the first embodiment, incorporated in the mobile objectfor selecting the operation mode. The force input manipulator 2 includesa manipulating handle 2 a which is the manipulating unit, andmanipulating handle holders 2 e, 2 e disposed substantially in parallelto each other, so as to support the end portions of the manipulatinghandle 2 a. The manipulating handle 2 a includes a pressure sensor 2 flocated halfway thereof for detecting a pressure in a longitudinaldirection along the manipulating handle 2 a, and the manipulating handleholder 2 e, 2 e respectively includes a pressure sensor 2 g, 2 g locatedhalfway thereof for detecting a pressure in a longitudinal directionalong the manipulating handle holder 2 e, 2 e.

The arrow A indicates for example a moving direction (Y-axis), and thearrow B indicates for example a left and right direction (X-axis).Locating two pressure sensors 2 g, 2 g in the moving direction (Y-axis)allows also detecting a rotating moment around a Z-axis orthogonal tothe X-axis and Y-axis, based on a difference between the pressure valuesdetected by the pressure sensors 2 g, 2 g.

The pressure sensors 2 f, 2 g, 2 g serve as the applied manipulatingforce detector (Ref. applied manipulating force detector 3 in FIG. 10),for detecting a force in the moving direction and in left and rightdirections, as well as a rotating moment, and transmitting the detectedresult to the operation mode selector (Ref. operation mode selector 4 inFIG. 10). The operation mode selector accordingly selects an operationmode based on the detected result, so that the mobile object 1 moves inthe desired operation mode.

FIG. 10 is a block diagram showing an outline of another control blockaccording to the present invention. A manipulating force applied to themanipulating handle 2 a, which is the manipulating unit, is detected bythe applied manipulating force detector 3. The applied manipulatingforce detector 3 is specifically the plurality of pressure sensors, asalready stated. At the operation mode selector 4, the appliedmanipulating force (applied manipulating force vector Fi) detected bythe applied manipulating force detector 3 is compared with the referencemanipulating force (reference manipulating force vector) determined inadvance and stored in the reference manipulating force storage unit 5,so as to decide the reference manipulating force closest to the appliedmanipulating force, and to thereby select the operation modecorresponding to the reference manipulating force. In other words, theoperation mode selector 4 decides the reference manipulating forceclosest to the applied manipulating force out of a plurality ofreference manipulating forces developed and stored in advance withrespect to a plurality of operation modes, and then selects theoperation mode corresponding to the reference manipulating force. Thereference manipulating force storage unit 5 may be a built-in memory ora portable auxiliary storage device such as a memory card containing thedata of each individual user.

The motion control signal generator 6 calculates the motion speed(rotation speed and rotation direction) required by the motors 8 e, 8 finstalled on the mobile object 1 for driving the rear wheels, accordingto the selected operation mode, and outputs a control signalcorresponding to the motion speed to the motor controllers 7 e, 7 f Themotor controllers 7 e, 7 f supply a predetermined driving current to themotors 8 e, 8 f respectively, according to the control signal from themotion control signal generator 6. In FIG. 10, the motors are shown asthe right rear wheel motor 8 e and left rear wheel motor 8 f, as anexample.

FIG. 11 is a flowchart showing a process of operation mode selection andoperating speed calculation, in the force input manipulator according tothe second embodiment. The following description is based on theassumption that the operation modes include three modes, namely thestraight travel mode, direction change mode (left turn or right turnmode) and rotation mode.

Firstly, the applied manipulating force detector 3 detects the appliedmanipulating force (applied manipulating force vector) including theforce along the X-axis and the force along the Y-axis detected by thepressure sensors (The X component of the applied manipulating force Fiis denoted as Fix, and the Y component as Fiy) (step S101).

It is decided whether an absolute value of a difference between twoforces along the Y-axis Fiy1 and Fiy2 detected by the pressure sensorsis lower than a predetermined threshold value ε (step S102), and if theabsolute value of the difference between the Fiy1 and Fiy2 is decided tobe lower than the predetermined threshold value ε (YES at S102), it isjudged that the Fiy1 and Fiy2 are substantially equivalent (=Fiy) (stepS103), and then a similar process to the first embodiment is performed.

If the absolute value of the difference between the Fiy1 and Fiy2 isdecided to be greater than the predetermined threshold value ε (NO atS102), a rotating moment Mi around the Z-axis is calculated (step S104).Then the rear wheel rotation speed and direction corresponding to thereverse rotating moment −Mi (minus Mi), which offsets the calculatedrotating moment Mi, is calculated (step S105).

Then the operation mode selector 4 calculates the similarity (proximity)to the reference manipulating force developed according to the appliedmanipulating force Fi and the operation mode and stored in the referencemanipulating force storage unit 5 (step S106). In other words, theoperation mode selector 4 calculates the magnitude of the projection(projected vector) of the applied manipulating force (i.e. the magnitude|Fis| of the projected straight travel vector Fis, the magnitude |Fic|of the projected direction change vector Fic, and the magnitude |Fir| ofthe projected rotating vector Fir), with respect to the referencemanipulating force corresponding to the operation mode (such as thestraight travel reference vector Fs, direction change reference vectorFc and rotating reference vector Fr).

The reference manipulating force corresponding to the largest (closest)projected vector out of the calculated projection magnitudes of theapplied manipulating force is decided and retrieved, and the operationmode corresponding to the decided and retrieved reference manipulatingforce is selected. For example, firstly it is decided whether theapplied manipulating force corresponds to the straight travel mode,depending on whether the magnitude of the projected straight travelvector Fis is the greatest (step S107). If the magnitude of theprojected straight travel vector Fis is decided to be the greatest (YESat S107), the operation mode selector 4 selects the straight travel mode(step S108). When the straight travel mode is selected, the motioncontrol signal generator 6 calculates the rotation speed and directionof the left and right rear wheels, taking into consideration therotation speed and direction calculated at the step S105 (step S109).This allows offsetting the rotating moment generated by the manipulationof the user, and thus causing the mobile object 1 to accurately movestraight.

If the magnitude of the projected straight travel vector Fis is decidednot to be the greatest (NO at S107), it is decided whether the appliedmanipulating force corresponds to the rotation mode, depending onwhether the magnitude of the projected rotating vector Fir is thegreatest (step S110). If the magnitude of the projected rotating vectorFir is decided to be the greatest (YES at S110), the operation modeselector 4 selects the rotation mode (step S111). When the rotation modeis selected, the motion control signal generator 6 calculates therotation speed and direction of the left and right rear wheels, takinginto consideration the rotation speed and direction calculated at thestep S105 (step S112). This allows offsetting the rotating momentgenerated by the manipulation of the user, and thus causing the mobileobject 1 to accurately rotate.

If the magnitude of the projected rotating vector Fir is decided not tobe the greatest (NO at S110), the operation mode selector 4 selects thedirection change mode (step S113). When the direction change mode isselected, the motion control signal generator 6 calculates the rotationspeed and direction of the left and right rear wheels, taking intoconsideration the rotation speed and direction calculated at the stepS105 (step S114). This allows offsetting the rotating moment generatedby the manipulation of the user, and thus causing the mobile object 1 tochange the direction in a desired turning radius.

Based on the rotation speed and direction of the left and right rearwheels calculated at the steps S109, S112 and S114, the motorcontrollers 7 e, 7 f accordingly determines an instruction value for themotors, and outputs the value as a motor instruction value (step S115).Repeating the foregoing steps according to the cases leads to achievingthe force input manipulator that can smoothly operate the mobile object1 based on the intention of the user. Also, incorporating a mobileobject provided with such a force input manipulator in a push cart or awalker so as to operate the push cart or walker can accomplish auser-friendly push cart or walker.

INDUSTRIAL APPLICABILITY

As described above in details, according to the first to the eighthaspects of the present invention, since a reference manipulating forceclosest to reference manipulating forces determined and stored inadvance according to an operation mode is decided, so as to select theoperation mode corresponding to the decided reference manipulatingforce, a user-friendly force input manipulator can be attained thatallows selecting the operation mode according to the intention of theuser, even when the user can only apply a limited force to themanipulating unit. Such force input manipulator offers a naturalmanipulating feeling also to an ordinary user.

The ninth to the eleventh aspects of the present invention provides anobject, a mobile object, a push cart and a walker provided with theforce input manipulator according to the first to the eighth aspects ofthe present invention. Therefore, an easy-to-use, user-friendly pushcart or walker can be attained.

1. A force input manipulator that operates an object according to amanipulating force applied to a manipulating unit, comprising: anapplied force detector which detects the manipulating force applied tothe manipulating unit; an operation mode selector which decides areference manipulating force closest to the detected manipulating forceapplied out of a plurality of reference manipulating forces stored inadvance in correlation with a plurality of operation modes, and selectsthe operation mode corresponding to the decided reference manipulatingforce; and a motion control signal generator which outputs a motioncontrol signal for controlling the motion of the object according to theselected operation mode.
 2. The force input manipulator according toclaim 1, further comprising means for developing and storing thereference manipulating force based on the applied manipulating force. 3.The force input manipulator according to claim 1, wherein the appliedforce detector is a biaxial force sensor which detects a force acting ina direction with respect to the object and in another directionintersecting the first mentioned direction.
 4. The force inputmanipulator according to claim 1, wherein the applied force detectorincludes a plurality of force sensors, out of which at least two sensorsare employed for one direction.
 5. The force input manipulator accordingto claim 1, wherein the operation mode is one of moving straight,changing a direction and rotating.
 6. The force input manipulatoraccording to claim 1, wherein the operation mode selector stores adecision region defined by a magnitude and acting direction of the forcewith respect to each reference manipulating force, so as to specify thedecision region to which the applied manipulating force belongs, basedon the magnitude and acting direction thereof, and thus to decide thereference manipulating force closest to the applied manipulating force.7. The force input manipulator according to claim 1, wherein theoperation mode selector has a function of deciding the referencemanipulating force closest to the applied manipulating force, based on adifference in direction between the acting direction of the appliedmanipulating force and that of the reference manipulating force.
 8. Theforce input manipulator according to claim 1, wherein the operation modeselector has a function of utilizing the magnitude and acting directionof the applied manipulating force and those of the referencemanipulating force to calculate a distance in a two-dimensional spacedefined by the magnitude and the direction, and deciding the referencemanipulating force closest to the applied manipulating force based onthe length of the calculated distance.
 9. A mobile object comprising theforce input manipulator according to claim 1, so as to move according tothe motion control signal output by the motion control signal generator.10. A push cart comprising the mobile object according to claim
 9. 11. Awalker comprising the mobile object according to claim
 9. 12. The forceinput manipulator according to claim 2, wherein the applied forcedetector is a biaxial force sensor which detects a force acting in adirection with respect to the object and in another directionintersecting the first mentioned direction.
 13. The force inputmanipulator according to claim 2, wherein the applied force detectorincludes a plurality of force sensors, out of which at least two sensorsare employed for one direction.
 14. The force input manipulatoraccording to claim 2, wherein the operation mode is one of movingstraight, changing a direction and rotating.
 15. The force inputmanipulator according to claim 2, wherein the operation mode selectorstores a decision region defined by a magnitude and acting direction ofthe force with respect to each reference manipulating force, so as tospecify the decision region to which the applied manipulating forcebelongs, based on the magnitude and acting direction thereof, and thusto decide the reference manipulating force closest to the appliedmanipulating force.
 16. The force input manipulator according to claim2, wherein the operation mode selector has a function of deciding thereference manipulating force closest to the applied manipulating force,based on a difference in direction between the acting direction of theapplied manipulating force and that of the reference manipulating force.17. The force input manipulator according to claim 2, wherein theoperation mode selector has a function of utilizing the magnitude andacting direction of the applied manipulating force and those of thereference manipulating force to calculate a distance in atwo-dimensional space defined by the magnitude and the direction, anddeciding the reference manipulating force closest to the appliedmanipulating force based on the length of the calculated distance.
 18. Amobile object comprising the force input manipulator according to claim2, so as to move according to the motion control signal output by themotion control signal generator.
 19. A push cart comprising the mobileobject according to claim
 18. 20. A walker comprising the mobile objectaccording to claim 18.